Override Test::More::is_deeply when use with "qw(is_deeply)"

I want to use difflet_is_deeply as is_deeply personally so I added
'''--exec "perl -Ilib -MTest::Difflet=is_deeply"''' to my ~/.proverc
but no effect.
Merge pull request #6 from hirose31/feature/override-test-more

Override Test::More::is_deeply when use with "qw(is_deeply)"